A time-division duplex (“TDD”) system typically uses a single physical channel and carrier frequency. Further, a TDD system shares the information channel for both transmission and reception, where the transmission and reception signals are spaced apart by multiplexing the two signals on a time basis. TDD systems may support data transmissions (e.g. data or digitized voice or video), transmitting a short burst of data in each direction. It is preferable that the transmission periods are relatively short, so that there is minimal time delay detected for voice transmissions and control messaging resulting from the time delays introduced by using TDD.
Conventionally TDD schemes specify a guard time between transmission and reception. The guard time provides a safety margin against symbol interference in the time between sequential operations such as transmission, encoding, decoding or switching. This guard time should be sufficient in order to allow the signals traveling from the remote transmitter to arrive before a master node transmission is started and the master node receiver is inhibited. In other words, the master node should wait until the entire transmission from the remote node is received before the master node may begin transmitting. When changing between transmission and reception many times a second, even a small guard time may reduce the efficiency of the system because the guard time is idle time and is not used for transmission of information. For TDD systems communicating over short distances, e.g. up to a mile, the guard time is normally small and has a minimal impact on system performance. For greater distances the size of the guard time may be problematic because it must be set to a higher value.
Guard time and transmission length contribute to the latency in the operation of a TDD system. Consequently TDD systems may not be suitable for use over long distances as the guard time increases and the channel efficiency decreases. Thus, it would be beneficial to develop a method and system that minimizes the latency and maximizes the frame efficiency in a time division multiplex communication system.